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A microfabricated atmospheric-pressure microplasma source operating in air

journal contribution
posted on 25.02.2008, 09:56 by Jeffrey A. Hopwood, Felipe Iza, S. Coy, D.B. Fenner
An atmospheric-pressure air microplasma is ignited and sustained in a 25μm wide discharge gap formed between two co-planar gold electrodes. These electrodes are the two ends of a microstrip transmission line that is microfabricated on an Al2O3 substrate in the shape of a split-ring resonator operating with a resonant frequency of 895 MHz. At resonance, the device creates a peak gap voltage of ~390V with an input power of 3W, which is sufficient to initiate a plasma in atmospheric pressure air. Optical emission from the discharge is primarily in the ultraviolet region. In spite of an arc-like appearance, the discharge is not in thermal equilibrium as the N2 rotational temperature is 500–700 K. The intrinsic heating of the Al2O3 substrate (to 100°C) causes a downward shift in the resonant frequency of the device due to thermal expansion. The temperature rise also results in a slight decrease in the quality factor (142 > Q > 134) of the resonator. By decreasing the power supply frequency or using a heat sink, the microplasma is sustained in air. Microscopic inspection of the discharge gap shows no plasma-induced erosion after 50 h of use.



  • Mechanical, Electrical and Manufacturing Engineering


HOPWOOD, J. ... et al, 2005. A microfabricated atmospheric-pressure microplasma source operating in air. Journal of Physics D : Applied Physics, 38, pp. 1698–1703.


© Institute of Physics Publishing

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This article is Restricted Access. It was published in the journal, Journal of Physics D: Applied Physics [© Institute of Physics Publishing]. The definitive version (doi:10.1088/0022-3727/38/11/009) is available at:





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